The invention relates generally to sorters or presorters for sheet material, such as mail, papers or documents and the like wherein the sorter includes a plurality of coded or tabbed leaves interconnected at one end and open at the other end for insertion of the documents during sorting. More particularly, the invention is directed to an improved sorter for mail or the like composed of a plurality of identical leaves, each coded to a specific address or addresses, and interconnected by a flexible, bellows binding so the space between any pair of adjacent leaves may be varied to accommodate the pieces inserted therebetween and further to permit the leaves to be laid upon a horizontal surface or table in a staggered offset relationship so the coded information on each individual leaf may be readily perceived during the mail sorting process and, at the completion of sorting, the sorter book and sorted mail may all be gathered up into a neat, superposed relationship to greatly facilitate removal of the sorted mail or documents from the sorter book.
Generally speaking, the assembly of mail or other documents by a device including a plurality of coded leaves connected together at one end and open at the other for insertion of mail, papers or other documents is well known. For example, U.S. Pat. No. 764,299 issued July 5, 1904 to J. J. Marsh shows a table for post office use including a number of coded, bent wire dividers having pronged ends for hinged insertion of the dividers into opposed, paired apertures on the table. If the space between dividers is too small to accommodate the mail being sorted, a divider may be removed and reinserted in another set of apertures to increase the spacing between dividers. This sorter is a large piece of furniture rather than a small, easily handled device, is designed to replace the usual pigeonhole case rather than supplement it, and there is no disclosure of multiple set coding of the sorter as set forth in detail hereinbelow.
A portable assorting case for use by a letter carrier is disclosed in U.S. Pat. No. 660,541, issued Oct. 23, 1900 to M. S. Field. The case has flexible, bellows type hinges along two adjacent sides, the other two sides being open for insertion of letters. The front of each divider is open so the letter carrier may read the address on the letter without removing it as he goes about his mail delivering duties. However, the case is not coded at all and is designed to be carried by the postman during delivery of mail rather than being used as a presorter of mail. Furthermore, since this expandable case is bound on two sides, it cannot be laid open in stair step fashion for use as a presorter and each space between adjacent leaves of the book is limited by the two side binding construction.
U.S. Pat. No. 1,797,355 issued Mar. 24, 1931 to H. H. Martin illustrates a presorter having leaves bound at one edge to thus form a presorter book, but the binding is rather inflexible, thus placing limitations on the amount of material that may be inserted between adjacent leaves, and multiple set coding of the type herein disclosed and claimed is not present. The Martin structure is also shown in U.S. Pat. No. 3,948,395 issued Apr. 6, 1976 to K. E. Thornton, this patent being directed to an edge tab structure.
Multipurpose coding by sets for the leaves of a presorter is disclosed to an extent in U.S. Pat. No. 2,876,907 issued Mar. 10, 1959 to G. W. Amberg but the coding sets are essentially unrelated to one another. This presorter further includes leaves of varying sizes so that the leaves are always in stair step, offset relationship and the binding thereof is relatively inflexible. More remote disclosures of presorters having stair-step leaves appear in U.S. Pat. Nos. 3,008,582 issued Nov. 14, 1961 to E. M. Kent and 3,876,077 issued Apr. 8, 1975 to C. E. Jones.
The prior art does not disclose a presorter having a plurality of leaves connected by a flexible bellows hinge along one edge of each leaf to form a presorter book which may be expanded open into a stair-step, offset arrangement of leaves, each leaf being multiple set coded on both faces so that the same sorter may be used for a series of progressive sorting steps in an overall sorting operation, such as arrangement of mail for delivery by a letter carrier.